1. Field of the Invention
This invention relates in general to hydrocarbon production, and more particularly to methods, computer readable medium, apparatus, and program code, for determining well characteristics and pore architecture for a hydrocarbon well.
2. Description of the Related Art
Water saturation can be a crucial property of oil reservoirs. It is not a parameter that is simple to predict, however. Industry standard practices use empirical functions which are linked to hard data and measurements through regression techniques which lead to pure statistical and meaningless parameters from a physics point of view. Of the numerous methods that have been developed over the years to predict/estimate water saturation, a capillary pressure-based method which employs the Leverett J-function is the most popular. The Leverett J-function is a dimensionless function of water saturation describing the capillary pressure within a reservoir, which uses the physical properties of rock as input terms. Other examples of methods which provide water saturation predictions include a capillary pressure-based method by Johnson (1987), a log-based method by Cuddy (1993), and a capillary pressure and log-based method by Skelt-Harrison and Skelt (1995).
The prior methods of predicting water saturation have two main pitfalls. First, they are mostly empirical and based on mathematical correlations. Hence, they are strictly valid only for specific conditions, formations, and/or environment. Also, the actual domain of applicability is defacto unknown. Second, the lack of relations to meaningful physical quantities and physics principles make the interpretation and validation heuristic. That is, prior methods fail to use or prove a link between the results and actual measurable physical quantities.